For mechanical work pieces with round cross-sections such as shafts and bores, surface texturing is important as the textured surface creates multiple small reservoirs for retaining lubricant. The surface texture typically includes dimples or indentations spaced apart in a predetermined or random fashion. Currently, for hard work pieces such as metal shafts and bores, surface texturing is done via machining or laser ablation, both of which require multiple operations on multiple machines, which is both time intensive and costly.
Machining entails removal of material from a substrate to leave a desired geometry. One example of surface texture creation by micro-machining is the use of a turning operation along with a micro-positioning system. This method allows for accurate shapes and tolerances, but is time consuming and expensive. Micro-machining may also result in an undesirable residual stress in the work piece.
Laser ablation, laser micro-milling and other laser texturing techniques have become popular because they can achieve submicron-sized features in hardened metallic surfaces with highly variable geometries. Recently, these methods have been used on a variety of automotive work pieces, mechanical seals and bearings. However, laser texturing does not allow for accurate control over the resulting dimple geometry. Further, the surface finish is generally poor if a fast process is desired, and laser texturing is both time intensive and costly as it must be performed after the work piece is machined, thereby requiring a separate process on a separate machine.
What is needed is a way to apply a texture surface to a work piece more efficiently than the currently available processes.